Nico di Angelo and the Horcrux Cave
by MissSadieKane
Summary: Nico was supposed to be looking for his cousin, Percy. He doesn't expect to meet the Goddess of magic and be sent back in time to a cave in the middle of nowhere, save a life, find a locket, and discover a whole new world. AU 1979,  Regulus lives .
1. Chapter 1

Disclaimer: I do not own the 'Harry Potter' series or 'Percy Jackson' series.

AN: I don't think this has been done before, so I'm giving it a go. In this chapter, Nico is thirteen, and Regulus is about seventeen or eighteen. Hope you all like it.

Chapter One: The Cave

Nico di Angelo felt himself sucked into a void. He saw flashes of scenery here and there, but otherwise, everything was in darkness. It was nothing like shadow travelling, but somehow he knew they had travelled – in time as well as in space. He was not happy.

Finally, the sensation stopped. Nico felt rather sick, but pretended he wasn't, and looked up at Hecate.

"So are you going to tell me what you want or not?" he asked the goddess standing beside him.

"I told you, no. You will find out in a minute," Hecate told him. Nico glared at her. "Oh and Nico, you'll need this." She held out a wooden stick to him.

"What do I need this for?"

"It's a wand. You'll be stuck without one here!" she said. Nico scowled.

"Anything else?"

"The date is 1979. Don't do anything stupid," she replied. Then she did whatever gods do, and disappeared.

…..

Nico was having a terrible day. First of all, he had been told that his cousin Percy had gone missing, so naturally he'd gone off shadow travelling to look for him. What he hadn't expected, though, was to bump into his now least favourite Goddess, and get sent back in time. He'd never been so angry with a Goddess before, and that included Persephone turning him into a common weed! How was he supposed to find Percy now! Unless Percy had also gotten himself sent back in time to the seventies, which was extremely unlikely. And what the Hades did Hecate want him to do anyway!

He had been too angry to notice at the time that the Goddess had dropped him off waist deep in water at the entrance to a cave. Being Hades son, and not on very good terms with his Uncle, Nico had been afraid of being drowned. He had walked into the cave, a tunnel that seemed to go on for miles, and had eventually found himself a dry spot, right at the back of the cave. This was where he has sitting now.

There were three main problems Nico was concerned about: firstly, he needed to get back into his own time and find Percy Jackson before Annabeth murdered him (actually if he was here, she couldn't get him anyway); secondly he was soaking wet and shivering with cold – if he didn't get dry soon, he would get ill. Thirdly, the tide was coming in, and the size of the dry spot was decreasing rapidly.

Ten minutes later when he was shivering violently, and standing ankle deep in the freezing water, Nico thought he heard someone coming towards him. He let himself become immersed in shadows so that no one could see him, and watched as a boy a little older than Percy, and a weird looking creature splashed through the water towards the back of the cave.

"Kreacher. You can't tell anyone in the family about this, understand? Now how do we get in?" Nico listened, as the boy addressed the strange creature. The creature called Kreacher muttered something about blood, and Nico watched in horror as the boy cut his own arm with a penknife and smeared the blood on the wall. It was most barbaric, but it seemed to have done something to the wall. A hole appeared, and Nico followed the two strangers through it into a large cavern. Inside was an enormous lake, with a green glow towards the centre.

He immediately sensed something was wrong. The lake was full of bodies. Bodies that weren't dead, or alive either. It wasn't right, and the young 'Son of Hades' could tell. He waited until the boy and Kreacher were sufficiently distracted by trying to retrieve a boat, before sending the awful creatures to his father to deal with. Hopefully, Hades would know what to do with the soulless bodies; otherwise Nico would be in a little bit of trouble when he returned home. If he ever got home, that was…

He watched as the boy and the creature climbed into the boat and started rowing towards the green glow. They were talking about a 'dark lord' and something called a 'Horcrux'. He assumed 'dark lord' meant his father, though he had no idea why they didn't just refer to him by his name. Nico didn't know what a 'Horcrux' was, but he could tell from the tone of voice that it was something bad. The boy wanted to destroy it. Nico guessed it was near the green glow, so shadow travelled towards it.

Unfortunately, the green glow was coming from an island, but it also extended a little into the lake. Nico groaned as he realised he was knee deep in water again, and walked the rest of the way onto the island. He blended back into the shadows, and watched as the boat moved slowly towards the island.

He noticed a stone basin in the centre of the island. It was full of green glowing liquid, but at the bottom of it, was a large golden locket. As the son of a 'Death God', Nico could sense the soul trapped within it. However, it wasn't a whole soul, it was a piece of one. Nico remembered his father telling him that the only was to split one's soul was to commit a terrible crime, such as cold-blooded murder. Who ever had trapped their soul in the locket must have been really evil, and they were trying to cheat death. Nico was disgusted.

"There it is, Master Regulus," said Kreacher. Nico assumed the boy's name was Regulus, and that the creature was talking about the Horcrux. The Horcrux must me the locket with the trapped piece of soul, and guessed they were going to try and retrieve it.

"Kreacher, I order you to make sure I drink all the potion. I want you to take the locket and swap it with this one," Regulus said. Nico watched as he took a slightly smaller locket out of his robes, and slipped a piece of paper in it. The boy then gave it to Kreacher. "When you are done, I want you to take it and leave me here. I order you to destroy the locket if you can."

Kreacher than began to scoop out the potion using a goblet, and started to feed it to Regulus. The boy drank the potion, and Nico could tell that it made the boy much weaker. After the third goblet full of the potion, Regulus's body began to shake, and he started yelling things about someone called Sirius and someone called Bella and Narcissa. The potion was obviously making Regulus see things that were not there, but Nico couldn't think of any other way to retrieve the locket.

"No! Please, Sirius, please don't leave. I need you!" Regulus shouted, his body writhing. Then he started shaking as if he was being tortured, and crying out for someone called Bellatrix to stop. He also started shouting for something to drink, to which Kreacher only responded to by giving the boy more of the potion. Regulus then screamed even more. Nico didn't know what to do. It seemed utterly wrong, and he knew that Kreacher wouldn't have a clue how to destroy it.

Finally, the basin was emptied. The boy moved towards the lake, to drink from it. Nico didn't stop him – he was sure the lake would no longer be able to do him any harm. Instead, he wrestled the locket off Kreacher. The house elf was extremely angry and tried to get the locket back, but Nico told him he knew how to destroy it. He got out his black sword, and pointed it at the locket, banishing the piece of soul to the underworld. His father could then send it the fields of punishment. He then told Kreacher to get out, and not to tell anyone what had happened.

Nico then paid his attention to Regulus. He had recovered slightly, after his drink from the lake, but was still pale and shivering. Nico knew he couldn't leave him like that, so asked if there was anywhere he could take him.

"Sirius. Take me to Sirius. The others will kill me for this," Regulus said. Nico didn't have a clue where Sirius was or even who he was, but shadow travelled out anyway. Anywhere was better than here, and perhaps Hecate or some other God would guide him to where he was supposed to go.

…..

Whether I continue this depends on how many reviews I get. If I continue, next chapter, Nico and Regulus will turn up at Sirius's house, and surprise the marauders. The Potters, are not yet in hiding. I know this is very AU, but I hope you like it anyway.

Please Review,

Sadie K.

PS: Please read my other stories, and check out my poll for Regulus in 'Finding Family'.


	2. Chapter 2

Disclaimer: I do not own 'Harry Potter' or 'Percy Jackson' or any of the characters in this story.

Thanks for all the reviews. I didn't expect this to get so much support.

**Chapter Two: The Order**

Hecate must have guided him, because as he grabbed Regulus and the locket and shadow travelled, he felt himself pulled in a certain direction. He made a mental note to repay her later. However, as he got closer to his destination, he felt some kind of force field working against him. He struggled against it, and fortunately was able to overcome it. Unfortunately, this meant that when he landed, he was very tired.

Nico landed on what appeared to be a table. About twenty people were sat around it, and were discussing some kind of issue. They all looked up in surprise, and Nico guessed correctly that they had never seen anyone shadow travel before. Exhausted from the shadow travel, be dropped Regulus, and keeled over himself.

…..

About an hour previously, Sirius Black and his best friend James Potter had been getting ready to go to an order meeting. They were waiting for Lily, who was having a shower after she and James had 'tried for a baby' the previous night. James himself was telling his best friend all about it, and what an entirely wonderful experience it had been with his Lily-flower. Sirius was wishing his best mate would leave out a few of the details of the incident, and talk about something else instead, such as the upcoming order meeting.

There was a knock on the door, which was then opened to reveal Sirius's other best friends, Remus and Peter. After some questioning to see if they were exactly who they said they were, they were let into the house where Lily soon joined them. The four marauders and Lily then apparated to the headquarters of the 'Order of the Phoenix' for the meeting.

Sirius found the meeting dull; he had other stuff on his mind to think about. A few days ago, his brother had come to him, asking for help. He had said he had quit the death eaters, and that he needed help with something. Sirius, of course, hadn't believed him for a second, and had shouted at him, telling him to leave the house and never come back. Sirius now felt slightly guilty about his reaction, but figured that his brother had been lying anyway, to trick him into going somewhere with him.

His thoughts were interrupted by a dark swirling patch of shadow appearing on the table in front of him. This took shape to form the figure of a boy, who looked as if he would be either in his second or third year at Hogwarts – far to young to apparate. What was most strange though, was that the boy appeared to be carrying Regulus, who was pale, bleeding and unconscious in his arms. Sirius felt a wave on concern for his brother rush over him. What on earth had happened to him?

The younger boy fainted, dropping Regulus's almost lifeless body, and a golden locket. The order members, stared blankly, none of them sure what to do. A known Death Eater lay unconscious on the table, next to a child, who had somehow apparated past the Headquarters protection! Everyone knew that the Headquarters were protected by the fidelius charm, and one could only find it if told where it was by Albus Dumbledore. Had Dumbledore told them? No, Dumbledore looked as confused as everyone else.

Fabian Prewett, who had decided to pick up the golden necklace, broke the silence. "Do you recognise this Sirius. Is it Regulus's?" he asked.

"No, Regulus has a locket, but it is smaller than that one," Sirius said. Fabian shrugged and handed the locket to Dumbledore, who started to examine it.

"It has the crest of Slytherin on it. I believe it used to belong to Salazaar Slytherin," said Dumbledore. "But why would Regulus and this boy have it?" he mused.

"It was in cave." It was Regulus that had spoken. His voice was quiet and raspy, as if he had not drunk anything in several days. Lily looked at him in concern, but was unsure what to do, as the boy was a known Death Eater – the whole thing might have been a trick. She settled for conjuring up a glass of water, which Regulus drank. "Thankyou," he said. Some colour appeared in the boy's cheeks.

Sirius, meanwhile, was intrigued as to what Regulus was doing in a cave and what the locket was for. Was this what Regulus had wanted help with? By the look of him, Regulus could have done with quite a lot of help. He didn't need to ask though. Regulus had seen the looks on people's faces and had decided to tell his tale of his own accord.

"It's a Horcrux," Regulus explained. Sirius gasped. He had read about them once, in a book that his Father had had in the study, and had forbidden him to read. Sirius, being Sirius, had of course gone and read it anyway, and had then wished he hadn't. The book had been vile! Dumbledore looked unfazed, as if the idea of Horcruxes were completely normal, but everyone else looked confused.

"A Horcrux is a device used to store a part of one's soul in," said Sirius. "Some people make them to become immortal, but you have to kill someone to make one." Most people were shocked at both the concept of Horcruxes, and the fact that Sirius knew all about them."

"So you read that book too, did you?" asked Regulus. The look on Sirius's face told him that he had, indeed, read 'the book'.

"It's not mine," Regulus said quickly. "It's Voldemort's. He asked for a house elf so…" he then proceeded to tell the order of how Voldemort had taken Kreacher to the cave, and made him drink the potion, how he had searched in all the books in the household library to find out what the locket was, and finally of his ordeal in the cave.

"And who is this?" asked Dumbledore, looking at the other boy.

"I don't know, but he saved my life, and destroyed the Horcrux," said Regulus.

"I think it is time we revived him, don't you?" said Dumbledore. He pointed his wand at Nico to wake him.

…..

AN: Sorry this is slightly shorter. Next chapter, Nico will be awake, and Regulus may get a chance to talk with him and Sirius.

Please review.

Oh, and if you like this, please have a look at 'Finding Family' and 'Not What You Think', which both follow the life of young Regulus.

Sadie K.


	3. Chapter 3

_Disclaimer: I am neither Rick Riordan nor J.._

_AN: Sorry this took ages. Please read the Authors note at the bottom._

Chapter Three

Nico stirred out of his deep slumber; he couldn't remember the beds at camp, or at his other home in the underworld, ever being this uncomfortable. It was then that he realised that he was in fact not lying on a bed, but on a long wooden table.

He opened his eyes groggily and looked around. There was an excess of twenty people seated around the table – most of which were between the ages of twenty and thirty. However, there was also one extremely old man with a long, white beard, and the young boy that he had helped. It was the old man who addressed him.

"Hello. Young Regulus has told us his side of the story. My name is Dumbledore. Who are you, and why are you here?" Nico assumed the boy who he had rescued was Regulus.

"My name's Nico. I'm a half blood," said Nico. He wondered what the others would make of that.

"There's nothing to be ashamed of Nico. Plenty of good witches and wizards are half bloods," said the old man. Nico couldn't help wondering whether the old man had a different definition of half blood to him. The old man had seemed very unsurprised, and from Nico's experience, even fellow demigods were usually amazed to hear that someone else shared their secret. He decided to go along with whatever this Dumbledore man thought.

"How did you know I was in the cave?" asked Regulus. "How did you know how to destroy that thing?"

Nico wasn't quite sure how to answer that first question. How did you tell someone that the goddess of magic sent you back in time to a random cave? He hadn't even known that Regulus would be in the cave!

He decided to tell part of the truth. "I was looking for my cousin, Percy Jackson, who went missing a few days ago," He began. Many of the people around the table were nodding - they all had friends that had gone missing. "He's fond of the water, so I thought maybe he might be somewhere on the coast when he got lost. I found myself caught out and the tide was coming in, so I retreated into the cave. When Regulus used his blood to open the door, I followed in the hope of it leading me somewhere warm and dry."

"How come Regulus didn't see you?" asked one of the redheaded twins.

Nico wasn't sure how to explain this so that mortals would understand, so decided to tell the truth. "I can make myself blend into the shadows – it's a sort of special abitity of mine." His audience looked intrigued, so Nico immersed himself in shadows to the extent that they could hardly see him. If they hadn't known that he was there, they wouldn't have been able to spot him at all.

"Wow," said a young man, who looked a lot like Regulus. "I've never seen or heard of anything like that before." Nico assumed they were closely related – most likely they were brothers, but they could have been cousins.

"I'm the only person I know of that can do it. Who are you, you look like Regulus?"

"Sirius Black. I'm Regulus's older brother," he said. Nico smiled – he'd guessed correctly.

"But how did you know about the Horcrux?" asked Regulus.

"I didn't really. I knew it was bad, so I just sent the horcrux part off to my Father. He knows how to deal with it."

"How? Did you use a port key or something?" asked Regulus. Nico didn't know what a port key was, but decided to play along anyway.

"Yeah. Like that."

"I don't really understand," said Regulus.

"Neither do I," thought Nico.

…..

_AN: Sorry that this is quite short, and took a long time. I don't really know how to continue this – I only thought it up as a little one shot, or 'what if', whilst I was writing something else. I didn't expect people to like it so much, but I will continue – it will just take quite a long time for me to think what to write. I am also concentrating on writing 'Not What You Think' and 'Finding Family'. I will also have a new chapter for my Triton fiction coming soon._

_Tell me if you have any extra ideas or scenes you would like me to put in._

_Please review._


	4. Chapter 4

_I'm really sorry but I don't think I will be continuing this story. I never really knew where it was going. If you would like a challenge, please rewrite or adopt this story._


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